* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Poppins', sans-serif;
  background: linear-gradient(135deg, #1f1c2c, #928dab);
  color: #fff;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 30px;
  overflow-x: hidden;
}

.container {
  width: 100%;
  max-width: 800px;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(15px);
  border-radius: 20px;
  padding: 25px;
  box-shadow: 0 8px 25px rgba(0,0,0,0.4);
  animation: fadeIn 1.2s ease-in-out;
}

header {
  text-align: center;
  margin-bottom: 30px;
  animation: slideDown 1s ease;
}

header h1 {
  font-size: 2.5rem;
  font-weight: 600;
  margin-bottom: 5px;
  color: #ffd369;
  text-shadow: 0 0 15px rgba(255, 211, 105, 0.6);
}

header p {
  font-size: 1rem;
  color: #eee;
  opacity: 0.85;
}

.card {
  background: rgba(255, 255, 255, 0.07);
  padding: 20px;
  border-radius: 15px;
  margin-bottom: 20px;
  box-shadow: 0 5px 20px rgba(0,0,0,0.25);
  transform: translateY(10px);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
  transform: translateY(0px) scale(1.02);
  box-shadow: 0 8px 25px rgba(0,0,0,0.35);
}

.card h2 {
  font-size: 1.3rem;
  margin-bottom: 15px;
  color: #ffd369;
  border-left: 5px solid #ffd369;
  padding-left: 10px;
}

.input-group {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 15px;
}

.input-group input, 
.input-group select {
  flex: 1;
  padding: 12px 14px;
  border-radius: 10px;
  border: none;
  outline: none;
  font-size: 1rem;
  transition: box-shadow 0.3s ease;
}

.input-group input:focus, 
.input-group select:focus {
  box-shadow: 0 0 8px #ffd369;
}

.input-group button {
  padding: 12px 18px;
  border: none;
  border-radius: 10px;
  background: linear-gradient(135deg, #ffd369, #ff9f1c);
  color: #222;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.input-group button:hover {
  transform: translateY(-2px) scale(1.05);
  box-shadow: 0 6px 15px rgba(255, 211, 105, 0.5);
}

ul {
  list-style: none;
  margin-top: 10px;
  max-height: 200px;
  overflow-y: auto;
  padding-right: 5px;
}

ul li {
  background: rgba(255, 255, 255, 0.15);
  margin-bottom: 8px;
  padding: 10px 12px;
  border-radius: 10px;
  font-size: 0.95rem;
  animation: fadeInUp 0.5s ease;
  transition: transform 0.3s ease, background 0.3s ease;
}

ul li:hover {
  transform: scale(1.02);
  background: rgba(255, 255, 255, 0.25);
}

.result-card {
  text-align: center;
}

.result-card button {
  background: linear-gradient(135deg, #ff6b6b, #ff3d3d);
  color: #fff;
  font-size: 1rem;
}

#results {
  margin-top: 15px;
  text-align: left;
}

#results p {
  background: rgba(0, 0, 0, 0.3);
  margin: 6px 0;
  padding: 10px;
  border-radius: 8px;
  font-size: 0.95rem;
  animation: fadeInUp 0.6s ease;
}

#calculate {
  padding: 12px 18px;
  border: none;
  border-radius: 10px;
  background: linear-gradient(135deg, #ffd369, #ff9f1c);
  color: #222;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.50s ease, box-shadow 0.25s ease;
}

#calculate:hover {
  transform: scale(1.1);
  box-shadow: 0 0 10px #ffd369;
}

@keyframes fadeIn {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-20px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(15px); }
  to { opacity: 1; transform: translateY(0); }
}

ul::-webkit-scrollbar {
  width: 6px;
}

ul::-webkit-scrollbar-thumb {
  background: #ffd369;
  border-radius: 4px;
}

ul::-webkit-scrollbar-track {
  background: rgba(255, 255, 255, 0.05);
}

.balance-card {
  padding: 12px 15px;
  border-radius: 12px;
  margin: 8px 0;
  font-size: 1rem;
  font-weight: 500;
  animation: fadeInUp 0.6s ease;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.balance-card:hover {
  transform: translateX(5px) scale(1.02);
  box-shadow: 0 4px 15px rgba(0,0,0,0.25);
}

.receive {
  background: rgba(46, 204, 113, 0.15);
  color: #2ecc71;
  border-left: 5px solid #2ecc71;
}

.pay {
  background: hsla(6, 100%, 51%, 0.15);
  color: #5d0b02;
  border-left: 5px solid #e74c3c;
}

.settled {
  background: rgba(189, 195, 199, 0.2);
  color: #ecf0f1;
  border-left: 5px solid #bdc3c7;
}